Examine source code of Echo - Mac App

{
  "manifest_version": 3,
  "name": "Echo",
  "version": "1.0.3",
  "description": "Remembers what you play in your browser so the Echo app for Mac can resume it from anywhere.",
  "icons": {
    "16": "icons/16.png",
    "32": "icons/32.png",
    "48": "icons/48.png",
    "128": "icons/128.png"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "echo@theodorehq.com",
      "strict_min_version": "121.0",
      "data_collection_permissions": {
        "required": [
          "none"
        ]
      }
    }
  },
  "permissions": [
    "tabs",
    "scripting",
    "alarms",
    "nativeMessaging"
  ],
  "host_permissions": [
    "http://127.0.0.1:17893/*",
    "http://localhost:17893/*",
    "*://*.youtube.com/*",
    "*://*.spotify.com/*",
    "*://music.apple.com/*",
    "*://*.tidal.com/*",
    "*://*.soundcloud.com/*",
    "*://*.bandcamp.com/*",
    "*://*.deezer.com/*",
    "*://music.amazon.com/*",
    "*://*.mixcloud.com/*",
    "*://*.pandora.com/*",
    "*://*.qobuz.com/*",
    "*://*.audiomack.com/*",
    "*://*.vimeo.com/*",
    "*://*.twitch.tv/*",
    "*://*.dailymotion.com/*",
    "*://*.iheart.com/*"
  ],
  "background": {
    "scripts": [
      "background.js"
    ]
  },
  "action": {
    "default_popup": "popup.html",
    "default_title": "Echo",
    "default_icon": {
      "16": "icons/16.png",
      "32": "icons/32.png",
      "48": "icons/48.png",
      "128": "icons/128.png"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*",
        "*://*.spotify.com/*",
        "*://music.apple.com/*",
        "*://*.tidal.com/*",
        "*://*.soundcloud.com/*",
        "*://*.bandcamp.com/*",
        "*://*.deezer.com/*",
        "*://music.amazon.com/*",
        "*://*.mixcloud.com/*",
        "*://*.pandora.com/*",
        "*://*.qobuz.com/*",
        "*://*.audiomack.com/*",
        "*://*.vimeo.com/*",
        "*://*.twitch.tv/*",
        "*://*.dailymotion.com/*",
        "*://*.iheart.com/*"
      ],
      "js": [
        "content.js"
      ],
      "all_frames": true,
      "run_at": "document_idle"
    }
  ]
}